Prepare the standard Cactus substrate. It’s extremely important that it has good drainage. Another thing of vast importance is that you sterilize the substrate before planting. You can use oven, or to make the process even faster, a microwave. All plants that belong to this subgenus are very sensitive, so it’s important to use fungicides after germination too.
Soak the substrate with water from below, until it absorbs enough water, so that it’s moist on the surface too.
Plant the seeds to the substrate, and then cover them with a very thin layer of substrate, use as much substrate as to you need to barely cover the seeds.
You can additionally moisturize the substrate with a sprayer, but be careful not to reveal the seeds.
It’s best to put the pot in a plastic freezer bag and close it, so it maintains the moisture.
Keep it somewhere bright, but don’t put it under direct sunlight. It should be exposed to the temperature between 77 to 86°F (25 to 30°C).
When the seed germinates, you can move the pot to a bit cooler place, room temperature should be 60 to 77°F (20 to 25°C).
Plastic bag kept for moisture should be taken away only after a few days, after the seeds germinate.
Seedlings shouldn’t be overwatered because it’s not good for the plant to be too moist, but you can’t allow for the substrate to completely dry off either, because that will significantly influence the development of the plant.